Messages in this thread | | | Date | Mon, 17 Feb 2014 15:50:27 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched/deadline: Test for CPU's presence explicitly |
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On Mon, Feb 17, 2014 at 09:12:33AM -0500, Boris Ostrovsky wrote: > A hot-removed CPU may have ID that is numerically larger than the number of > existing CPUs in the system (e.g. we can unplug CPU 4 from a system that > has CPUs 0, 1 and 4). > > Thus the WARN_ONs should check whether the CPU in question is currently > present, not whether its ID value is less than num_present_cpus(). > > Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Thanks!, please also always CC the author of the code in question.
> --- > kernel/sched/cpudeadline.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > index 045fc74..5b8838b 100644 > --- a/kernel/sched/cpudeadline.c > +++ b/kernel/sched/cpudeadline.c > @@ -70,7 +70,7 @@ static void cpudl_heapify(struct cpudl *cp, int idx) > > static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl) > { > - WARN_ON(idx > num_present_cpus() || idx == IDX_INVALID); > + WARN_ON(!cpu_present(idx) || idx == IDX_INVALID); > > if (dl_time_before(new_dl, cp->elements[idx].dl)) { > cp->elements[idx].dl = new_dl; > @@ -117,7 +117,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, > } > > out: > - WARN_ON(best_cpu > num_present_cpus() && best_cpu != -1); > + WARN_ON(!cpu_present(best_cpu) && best_cpu != -1); > > return best_cpu; > } > @@ -137,7 +137,7 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid) > int old_idx, new_cpu; > unsigned long flags; > > - WARN_ON(cpu > num_present_cpus()); > + WARN_ON(!cpu_present(cpu)); > > raw_spin_lock_irqsave(&cp->lock, flags); > old_idx = cp->cpu_to_idx[cpu]; > -- > 1.8.1.4 >
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